1. Field of the Invention
The present invention relates to a disk drive, and more particularly, to a base member of a disk drive having a clock window to insert a clock head to write servo track information on a disk in the disk drive.
2. Description of the Related Art
Hard disk drives (HDDs), which are data storage devices used for computers, use read/write heads to reproduce and record data with respect to a disk. In the HDD, the read/write head performs its functions while being moved by an actuator to a desired position in a state of being lifted to a predetermined height from a recording surface of a rotating disk.
FIG. 1 is an exploded perspective view illustrating the configuration of a conventional hard disk drive. FIG. 2 is a perspective view illustrating a state in which a clock head is inserted in the hard disk drive of FIG. 1. FIG. 3 is a vertical sectional view illustrating a hard disk drive taken along line A-A′ shown in FIG. 2.
Referring to FIGS. 1 through 3, a spindle motor 30 to rotate a disk 20 and an actuator 40 to move the read/write head to reproduce and record data to a desired position on the disk 20 are installed on a base member 11 of a hard disk drive.
The actuator 40 includes: a swing arm 42 rotatably coupled to a pivot bearing 41 installed on the base member 11; a suspension 43 installed at one end portion of the swing arm 42 and supporting a slider, on which the read/write head is mounted, elastically biased toward a surface of the disk 20; and a voice coil motor (VCM) 45 to rotate the swing arm 42. The voice coil motor 45 is controlled by a servo control system, and rotates the swing arm 42 in a direction according to Fleming's left hand rule by the interaction between current applied to the VCM coil (not shown) and a magnetic field formed by a magnet (not shown). That is, when the power of the hard disk drive is turned on and the disk 20 starts to rotate, the voice coil motor 45 rotates the swing arm 42 counterclockwise to move the read/write head above a recording surface of the disk 20. In contrast, when the power of the disk drive is turned off and the disk 20 stops rotation, the voice coil motor 45 rotates the swing arm 42 clockwise, so that the read/write head is moved away from the recording surface of the disk 20.
A cover member 12 is assembled to the upper portion of the base member 11 using a plurality of screws 19. The cover member 12 protects the disk 20 and the actuator 40 by encompassing the same, and prevents intrusion of dust and humidity into the disk drive.
A circulation filter 50 to filter particles inside the disk drive, is provided at a corner of the base member 11.
In the disk drive having the above configuration, servo track information is written on the surface of the disk 20 for the read/write head to rapidly and accurately access a predetermined position on the disk 20, which is referred to as servo track write (STW). For the STW, a clock window 60 that is a through hole, is positioned at a side wall of the base member 11. A clock head 70 is inserted into the disk drive through the clock window 60 to write servo information on the disk 20. When the STW is completed, the clock head 70 is removed from the clock window 60 and the clock window 60 is sealed with a sealing tape 80 so that intrusion of dust and humidity into the disk drive is prevented.
But with a trend towards a more compact disk drive, the height of the disk drive decreases so that the height of the base member 11 decreases. Accordingly, the size of the clock window 60 which must still accommodate the clock head 70, is relatively larger compared to the more compact base member 11. Thus, a space to attach the sealing tape 80 on the side surface of the base member 11 is reduced, so that the sealing tape attachment area is obtained by cutting part of the edge of the cover member 12. But such cutting of part of the cover member 12 deteriorates the rigidity of the cover member 12.
To solve the above problem, as is shown in FIG. 4, instead of positioning the clock window on the base member 11, the clock head 70 is disposed above the disk 20 to write servo information on an upper surface of the disk 20 prior to the cover member 12 being attached to the base member 11. But in this case, since dynamic characteristics of the disk drive change before and after the cover member 12 is attached, the quality of the STW may deteriorate. Furthermore, when the STW needs to be performed again, the cover member 12 must be removed, which lowers work efficiency.
In another conventional STW method, servo information is written on a disk at a different place, and then the disk is assembled to the spindle motor. But in this case, to perform STW again, complicated steps are required, such that a cover member is opened, the disk is separated from the spindle motor, servo information is written on the disk, and then the disk and the cover member are re-assembled. Thus, this method is disadvantageous, in that the STW quality deteriorates due to a change in the dynamic characteristic of the disk drive, and the work efficiency is lowered.
Japanese Patent Application Publication No. 7-220423 discloses a base member with a clock window that is punched. The clock window is positioned on a bottom plate of the base member toward a side wall. The clock window is sealed with a cover manufactured of plastic resin after the STW is performed. According to this configuration, however, since the clock window is positioned on the bottom plate of the base member by penetrating the same, the rigidity of the base member is reduced. Furthermore, such a configuration is difficult to be applied to a thin base member corresponding to the recent trend towards the more compact disk drive.